Granted Patent
Utility
US 4,337,378 · App. 06/273,842
On-hook/off-hook detector circuit
Inventor:
Harold L. Davis
Patented Case
View Patent ↗
Granted: Jun 29, 1982
Filed: Dec 22, 1980
Inventor
Harold L. Davis
Assignee (at issue)
Mostek Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.